MIDTERM 2 Flashcards
what are the names of all the common ionic latices?
- CsCl
- rock salt (NaCl)
- wurtzite (ZnS)
- zinc blende (ZnS)
- fluorite (CaF2)
- perovskite (ABX3)
what is the CN and structure of CsCl?
CN = 8 Structure = bcc
what is the CN and structure of rock salt?
CN = 6 Structure = ccp/fcc with cation in all O holes
what is the CN and structure of zinc blende?
CN = 4 Structure = ccp/fcc with cation in half T holes
what is the CN and structure of wurtzite?
CN = 4 Structure = hcp with cation in half T holes
what is the CN and structure of Fluorite?
CN = 8:4 (cation:anion) Structure = ccp/fcc with anion in all T holes
what is the structure of perovskite?
Structure = normal ccp/fcc arrangement between cations & anions, but there’s a single cation in middle of cube (like bcc structure) - single cation sits in 1/4 of O holes
what is the approximate radius ratio value of CN = 8?
r+/r- = 0.7
what is the approximate radius ratio value of CN = 6?
r+/r- = 0.4
what is the approximate radius ratio value of CN = 4?
r+/r- = 0.2
what is the approximate radius ratio value of CN = 3?
r+/r- = 0.15
when is Z+ and Z- in born-mayer equation changing?
when comparing 2 different ionic solids with different cation and anion charges
what is r0 in born-mayer equation changing?
when comparing 2 different ionic solids that have the same anion and cation charges, but they’re “electron clouds” are different sizes - aka. small molecules therefore with low amount of orbitals vs. larger molecules therefore with more orbitals (produces non-ionic r0)
when can’t the born-mayer equation predict a molecule’s stability?
when its either a polarizable atom/element OR the bonding isn’t ionic (non-ionic r0)
what elements are polarizable?
- large anions OR small cations with high charges
how to tell which molecule is more stable using the born-mayer equation?
the one with the larger U(r0) value
what is a schottky defect?
intrinsic (stoichiometric) defect where one anion & cation are randomly missing from rock salt structure
what is a frenkel defect?
intrinsic (stoichiometric) defect where an ion is displaced off lattice site & fills another site that is normally empty
what is an extrinsic defect?
doping with vacancies
what are p-doped and n-doped semiconductors?
intentionally added point defects
what is a substitutional solid?
a point defect where an ion from outside structure directly replaces an ion of same charge
what is an interstitial solid?
a point defect where small ions enter empty interstitial sites (spaces between lattice)
what is an edge dislocation?
plane of atoms that goes part way through the structure (looks like wood grain)
what is a screw dislocation?
slip of plane in crystal structure (looks like staircase OR atoms sitting directly on top of each other)
what is the schrodinger equation for a 1D box?
(−h2)/(8π^2 m)∗d^2/(dx^2 ) Ψ(x) = EΨ(x)
what does a general wavefunction look like?
Ψ(x)=asin(nπx/L) OR Ψ(x)=asin(2πx/λ)
what does a general eigenvalue look like?
-(2π / λ)^2 * asin(2πx/λ)
what does the Ĥ operator look like?
(−h2)/(8π^2 m)∗d^2/(dx^2 )
what is a in the schrodinger equation?
√(2/L)
what does the normalization factor look like?
a^2 (L/2)=1
what does a laplacian look like?
∇^2=(−h^2)/(8π^2 m)
what are the radial and angular parts of the wavefunction?
radial = R(r) angular = Y(θ,Φ)
describe what energy is used in the particle in a box model?
- only specific values of energy allowed (V = 0 and V = ∞) therefore only kinetic energy is used
- kinetic energy = T=h2/(2me λ^2 )
describe what wavelengths are allowed in the particle in a box model?
1/2 cycle λ = 2L
1 cycle λ = L
1 & 1/3 cycle λ = 2L/3
2 cycles λ = L/2
energy (T) differences between allowed differences in particle in a box model?
1/2 cycle (T1) = h2/(2me) * (1/4L^2)
1 cycle (T2) = 4 T1
1 & 1/3 cycle (T3) = 9 T1
2 cycles (T4) = 16 T1
